Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
  • C06B23/009—Wetting agents, hydrophobing agents, dehydrating agents, antistatic additives, viscosity improvers, antiagglomerating agents, grinding agents and other additives for working up
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
  • C01C1/00—Ammonia; Compounds thereof
  • C01C1/18—Nitrates of ammonium
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05C—NITROGENOUS FERTILISERS
  • C05C1/00—Ammonium nitrate fertilisers
  • C05C1/02—Granulation; Pelletisation; Stabilisation; Colouring

Definitions

• the present invention is concerned with a method of lowering the tendency towards caking and setting of ammonium nitrate and with providing ammonium nitrate having a greatly reduced tendency towards caking and setting to a hard mass on storage.
• the invention is also concerned with solid ammonium nitrate products which include said ammonium nitrate having a greatly reduced tendency towards caking and setting.
• Ammonium nitrate is an intensely hygroscopic compound and its tendency to cake and set on storage, which is believed to be due to the formation of crystalline bridges from a saturated solution which is formed between adjacent particles of ammonium nitrate on absorption of moisture and which crystallises when changes occur in atmospheric conditions, is an extreme inconvenience in the handling of ammonium ntrate whether in bulk or in bags or in its use in explosives.
• ammonium nitrate when ammonium nitrate is provided with a thin surface coating of certain aromatic dyestufis, as for example by crystallisation from an aqueous solution containing said dyestufi in solution, the resulting ammonium nitrate at least in the crystal form IV exhibits a greatly reduced tendency to caking and setting, and ammonium nitrate treated with e. g. the ammonium or calcium salt of tri-sulphonated para-para-para-triaminotritolyl carbinol anhydride (i. e. the ammonium or calcium salt of tri-sulphonated New Magenta) has been used successfully in preventing the caking and setting of ammonium nitrate used for the production of explosive compositions.
• ammonium or calcium salt of tri-sulphonated para-para-para-triaminotritolyl carbinol anhydride i. e. the ammonium or calcium salt of tri-sulphonated New Magenta
• This dyestulf is of a magenta colour. Although only a very small pro portion of this dyestutf and the other sulphonated aromatic dyestulfs whose employment has been proposed is required the resulting ammonium nitrate has an intense colour.
• ammonium nitrate of reduced tendency to caking and setting on storage consists of discrete ammonium nitrate particles carrying on their surfaces a deposit comprising a salt soluble in a saturated aqueous ammonium nitrate solution at 20 C. of at least one compound definable as a condensation product of 1 mol. of formaldehyde and 2 mols. of a naphthalene monosulphonic acid.
• the method for the production of ammonium nitrate of reduced tendency to caking and setting on storage comprises effecting crystallisation of an aqueous solution of ammonium nitrate containing, reckoned on the weight of the dry ammonium nitrate particles, from 0.01% of a salt soluble in a saturated aqueous ammonium nitrate solution at 20 C. of at least one compound definable as a condensation product of 1 mol. of formaldehyde and 2 mols. of a naphthalene monosulphonic acid.
• the method for the production of ammonium nitrate of reduced tendency to caking and setting on storage comprises spraying an aqueous solution of a salt soluble in a saturated ammonium nitrate solution at 20 C. of at least one compound definable as a condensation product of 1 mol. of formaldehyde and 2 mols. of a naphthalene monosulphonic acid over the surfaces of previously formed ammonium nitrate particles.
• said compound which is a disulphonic acid of a dinaphthylmethane the sulphonic acid groups are in the rings to which the methylene group is not attached and are in one of the at positions in one naphthyl group and in one of the :1 positions in the other naphthyl group or in one of the 13 positions in one naphthyl group and in one of the 18 positions in the other naphthyl group or in one of the at positions in one naphthyl group and in one of the 8 positions in the other naphthyl group depending upon whether naphtha-- lene-a-sulphonic acid, naphthalene-e-stllphonic acid, or an equimolecular mixture of these is reacted with formaldehyde or its equivalent, preferably in the presence of sulphuric acid or hydrochloric acid, as for example in accordance with the method described in Canadian specification No. 347,865 or U. -'S. specification No.
• the disulphonic acids of dinaphthylmethane Will be referred to as diet, 13:13 or cup-disulphonic acids of dinaphthylmethane according to whether the compound is derived respectively by reacting with formaldehyde or its equivalent naphthalene-a-sulphonic acid, naphthalene- Beulphonic acid, or an equimolecular mixture of these two naphthalenesulphonic acids.
• ammonium nitrate IV normally crystallises from saturated solution as prisms or needles
• the presence-of small concentrations of the aforesaid salts of disulphonic acids of dinaphthylmethane in the crystallising solution results in the formation of laths, plates, or scale showing ⁇ 010 ⁇ faces.
• These modified crystals are of reduced mechanical strength, and thus it is assumed that the strength of the bridges of recrystallised material which forth between adjacent particles of ammonium nitrate in the presence of said salts is reduced. It is observed that the 5:5 isomer exerts a somewhat greater effect on the prevention of setting than the am and 11: 3 isomers.
• Quantities of the soluble salts of the aforesaid disulphonic acids of dinaphthylmethane from at least approximately 4 0.01% reckoned on the. weight of the dry ammonium nitrate particles are effective, but it is preferred to employ from 0.025% and the invention maybe put into effect by dissolving the soluble salt of the aforesaid dissolve it in water and spray the resulting solution over the surfaces of the previously formed ammonium nitrate particles, and bring about the evaporationof the water while keeping the ammonium nitrate particles in motion.
• the solid ammonium nitrate particles will usually be first obtained at a temperature exceeding 32.3 C.,'and it is essential that the particles be continuously agitated until the temperature falls below 32.3 C. or until the residual moisture is driven off.
• the ammonium nitrate so treated must be stored at a temperature not exceeding 32.3 C.
• Example 1 The sodium salt of fl:,8-disulphonic acid of dinaphthyh methane is prepared by heating under gentle reflux for 24 hours a mixture of 3.3 partsby weight of 5-naphthalenesulphonic acid, 1.9 parts by weight of an aqueous solution of formaldehyde (37% w./v.) and 1.9 parts by weight of sulphuric acid (s. g. 1.84) in '10 parts by weight of water and neutralising the resul-ting -liquor with a sodium hydroxide solution. r
• the surfaces of ammonium nitrate granules produced bya spray crystallisation process -of particle size- 30' to 100 B. S. S. are treated while still hot with a aqueous solution of the sodium salt of said fi:5-disulphonic acid of dinaphthylmethane, in an amount such that the ammonium nitrate'will acquire a surface coating of 0.05% of the said salt.
• Thegranules are dried with mechanical agitation.
• the dry product preserves the. original form and white appearance -of the granules and is free running and resistant to settingfor at least nine months when stored indoors in cardboard containers with loosely fitting lids.
• Example 2 The procedure'is the sameas in Example '1, except that the said sodium-saltof -m:a-disu1phonic acid of dinaphthylmethane is used inplacc of' the 52;? isomer.
• Example 5 Thesodium saltzof mzfi disulphonicacid of dinaphthylmethane "is prepared by heating under gentle reflux for 24. hours a mixture of 20.8 parts by Weightofa-naphthalenesulphonie acid, 20.8.parts by weight of [i-naphthalenesulphonie acid,.1l.0 parts. by. weight of aqueous formaldehyde solution (37% w./ v.) and 12.5 parts by weight of sulphuric .acid (s. g. L84)- in 44 parts by weight of water. and neutralising the resulting liquorwith a sodium hydroxide solution.
• Theprocedure. is the same as for .Examplefl, except that, the sodiumsalt of said -a:p-disulphonic acid of dinaphthylmethane is used in place of the 5: 8 isomer. Aggregatesof thin scales and plates showing ⁇ 010 ⁇ faces are obtained on slow cooling of a 1% solution in saturated ammonium nitrate solutiornand with 0.1% coating of the agent ,the dricdproduct shows improved resistance to setting...
• Ammonium nitrate. of reduced tendcncy to caking and .settingmn storage 4 comprising discrete ammonium nitrate.particlescarrying on their surfacesa deposit of at least one salt: of a'n-acidselectedfrom the group consistingtof the aux, 5:,8' and-e25 disulphonic acids of dinaphthylmethanes, said salt being soluble in a saturated aqueous ammonium nitrate solution at 20 C.
• Ammonium nitrate asclaimedinclaim1 wherein the quantity of thesol-ublesalt of the aforesaid disulphonioacids of dinaphthylmethane is at least approximately 0.01% reckonedon the weight of the dry ammonium nitrate particles.
• Ammonium nitrate according to claim 1 wherein the azfl-disulphonic acid is the condensation product of formaldehyde and an .equimolecular mixture of naphthalenea-sulphonic acid and naphthalene-fi-sulphonic acid.
• a method for the production of ammonium nitrate ofreduced tendency to cakingand'setting on storage which-comprises effecting crystallisation of an aqueous solution: of ammoniunr nitrate containing, reckoned on the weight of the dry ammonium-nitrate particles, from 0.01% of at least one salt of an acid selected from the group consisting of the am, 5:13 and otfifi' disulphonic acids of dinaphthylmethanes, said salt being soluble in a saturated aqueous ammonium nitrate solution at 20 C.
• a method as claimed in claim 7 which comprises effecting the direct crystallisation of the aqueous solution of ammonium nitrate containing the said salt.
• a method as claimed in claim 7 which comprises efa fecting the granulation of an aqueous solution of ammonium nitrate containing the said salt.
• a method for the production of ammonium nitrate of reduced tendency to caking and setting on storage which comprises spraying an aqueous solution of at least one salt of an acid selected from the group consisting of the aim, 5:5 and 11:6 disulphonic acids of dinaphthylmethanes, said salt being soluble in a saturated aqueous ammonium nitrate solution at 20 C. over the surfaces of previously formed ammonium nitrate particles.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)

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Citations (1)

• 0
  • BE BE529255D patent/BE529255A/xx unknown
  • NL NL86812D patent/NL86812C/xx active
• 1953
  • 1953-06-01 GB GB15174/53A patent/GB743602A/en not_active Expired
• 1954
  • 1954-04-19 US US424279A patent/US2782096A/en not_active Expired - Lifetime
  • 1954-04-28 FR FR1104433D patent/FR1104433A/fr not_active Expired
  • 1954-05-08 CH CH329358D patent/CH329358A/de unknown
  • 1954-05-29 DE DEI8705A patent/DE960629C/de not_active Expired

Patent Citations (2)

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